Stop button allows you to stop running capture.

The first scrolling area show received packets.

The second scrolling area show details about the selected packet.

Filters are updated when closing the window.

Tcp filter was unchecked so tcp packets automatically vanished.

Modifying a packet sends you to the forging tab, where all fields are automatically set to the selected packet fields. Then you can click on "forge" to send the packet.

Next and Previous buttons allow you to modify the different headers.

Reset button clear all fields and let you forge a new packet from scratch.

Here is the result when clicking on next on ethernet header, it sends you to next header: the IP header